Light pipes are devices that are used to transmit light over relatively short distances. Typically, light pipes are fabricated as clear glass or plastic rods. Light entering one end of a light pipe travels the length of the rod and is emitted at the rod's opposite end.
Light pipes are used in numerous applications. For example, it is common for printed circuit boards, disk drives and other components to include status LEDs. When a component of this type is included in a cabinet or other housing, the status LED may not be externally visible. In these cases, a light pipe may be used to convey the light produced by the status LED to a point outside of the cabinet. In this way, the operational status of the component may be assessed without having to open the cabinet.
In many cases, a single application will require a group of light pipes. This occurs, for example, when a printed circuit board or other component includes a group of LEDs. Making these LEDs visible from outside of an enclosing cabinet requires one light pipe for each LED.
To minimize production costs, a group of light pipes may be fabricated as a light pipe array. A light pipe array is an assembly, preferably one-piece, consisting of a group of light pipes joined by an interconnecting portion known as a runner. Light pipe arrays reduce costs by allowing a group of light pipes to be created using a single molding operation. Costs are further reduced because the entire light pipe array is installed as a single assembly.
Unfortunately, in light pipe arrays, there is a tendency for light traveling through a given light pipe to contaminate the remaining light pipes. This contamination occurs because light traveling through any of the light pipes has a tendency to enter the runner interconnecting the light pipes. Once inside the runner, the light enters and contaminates the remaining light pipes.
Contamination degrades the effectiveness of a light pipe array. Specifically, contamination can make a light pipe that is not intended to be illuminated appear to be partially or fully illuminated. Additionally, in cases where adjacent light pipes are intended to carry different colors of light, contamination can cause a blending of colors.
As a result, there is a need for light pipe arrays that can be molded as a single-piece assembly and exhibit little or no contamination between the included light pipes.